• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.34-40
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• 2000

In the tungsten industry, molybdenum wire which used as the center supporter for coil shape tungsten wire was removed. Nitric acid dissolution method which used prevalently up to the present, takes nitric acid as major component and use noxious material such as sulfuric acid and hydrochloric acid remove molybdenum wire which used as center supporter by dissolve selectively within the range of no damage on tungsten wire. Mixed acid waste water occurred to the process were difficult to be decomposed by the conventional methords. This mixed acid waste water was treated by ozone, and It was obtained using possible by-product through the treatment waste water. For the three reactors with the same volume ; Blank reactor, Disturbance plate reactor, Packed-bed reactor ; the results were as follows : For the blank reactor COD removal efficiency in the pH = 4 (HRT : 6hr) was 28.5%, COD removal efficiency in the pH = 7 (HRT : 6hr) was 28.6%, and COD removal efficiency in the pH = 10 (HRT : 6hr) was 27.8%. For the disturbance plate reactor COD removal efficiency in the pH = 4 (HRT : 6Min.) was 86.5%, COD removal efficiency in the pH =7 (HRT : 6Min.) was 84.4%, and COD removal efficiency in the pH = 10 (HRT : 60Min.) was 86.8%. For the packed-bed reactor COD removal efficiency in the pH = 4 (HRT : 40Min.) was 76.0%, COD removal efficiency in the pH = 7 (HRT : 40Min.) was 81.3%, and COD removal efficiency in the pH = 10 (HRT : 40Min.) was 84.6%. After O3 treatment using possible by-product(Na2SO4) was 150g/ℓ.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.173-186
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• 1993

The purpose of this study is to observe the morphological changes of prepared dentin surfaces by 5 dentin conditioning agents. Freshly extracted 48 healthy human molars were used in this study. The teeth were stored at $4^{\circ}C$ physiologic saline solution befor experiment. The teeth were cross-sectioned to expose dentin below 3.0mm at the cusp tip and above 2.0mm at the cemento-enamel junction with Crystal Cutter (MC411 D, Maruto Co., Japan). The specimens were then divided into 12 groups. The sectioned dentin surfaces in group 1, 3, 5, 7, 9, and 11 were prepared with No. 301 diamond point under air-water spray and those in group 2, 4, 6, 8, 10, and 12 were prepared with No. 700 carbide bur. The prepared dentin surfaces were conditioned with Nitric acid, Citric acid, Poly acrylic acid, EDTA, and Phosphoric acid. All the specimens were gold-coated with Eiko ion coater (Eiko-engineering Co.) and observed in Hitachi S-2300 Scanning electron microscope at 20 KV. The following results from this study were obtained; 1. The dentinal smear layers prepared with diamond point were compacted than those prepared with the carbide bur. 2. The dentinal smear layers prepared with diamond point or carbide bur were thick but after treatment of dentin conditioning agents smear layers were removed almost. 3. Irrespective of the uses of the diamond point or the carbide bur the morphological changes of dentin surfaces treated with the same conditioning agents were similar. 4. Treatment of nitric acid and EDTA was a little effect in removing dentinal smear layer. 5. Treatment of citric acid and phosphoric acid removed the smear layer very effectively and showed dissolution of peritubular dentin and opening of dentinal tubules.

• Applied Chemistry for Engineering
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• v.27 no.3
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• pp.319-324
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• 2016

In this study, pitch-based carbon fibers in the acid were radiated with an electron beam to modify their surface, and surface changes were investigated according to each treatment conditions. Nitric acid and hydrogen peroxide were used as a drenched acidic solution and an electron beam dose was set to 200 and 400 kGy. The use of nitric acid introduced more oxygen functional groups on carbon fiber surfaces than that of using hydrogen peroxide, and also introduced nitrogen functional groups into the carbon fiber surface. In addition, oxygen functional groups introduced on carbon fiber surface increased as the electron beam dose increased due to the fact that the oxidizing material can be easily formed by e-beam radiation in nitric acid than the hydrogen peroxide, and also the higher energy electron beam dose can help forming more oxidizing materials. Moreover, the generation of C=O functional groups was favorable when using nitric acid because oxidizing C-OH functional groups to the C=O functional groups mainly occurred by $NO_2$ radicals generated by the electron beam radiation in a nitric acid solution.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.1
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• pp.6-11
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• 2018

The anodic oxidation behavior of Si-containing aluminum alloy for diecasting was investigated. Especially, the property changes during anodization both on aluminum 1050 and 9 weight percentage silicon containing aluminum (Al-9Si) alloys were analyzed by the static current test. In order to fabricate a uniform anodic oxidation film by effect of Al-Si compound, nitric acid containing hydrofluoric acid had been used as a desmutter for aluminum alloy after alkaline etching. It was found that the level of voltage of Al-9Si alloy during the static current test was almost as double as higher than aluminum 1050 through anodization. By adding hydrofluoric acid in the nitric acid electrolyte, the silicon compound on the surface was removed, and the optimum amount of added hydrofluoric acid could be derived. It was also observed that the size of silicon compound formed on the surface could be refined by heat treatment at $500^{\circ}C$ and followed water quenching.

• Preventive Nutrition and Food Science
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• v.18 no.1
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• pp.38-44
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• 2013

The protective effect of Polyopes lancifolia extract on high glucose-induced oxidative stress was investigated using human umbilical vein endothelial cells (HUVECs). High concentration of glucose (30 mM) treatment induced HUVECs cell death, but Polyopes lancifolia extract, at concentrations of 25, 50, and $100{\mu}g/mL$, protected cells from high glucose-induced damage. Furthermore, thiobarbituric acid reactive substances, intracellular reactive oxygen species, and nitric oxide levels increased by high glucose treatment were effectively decreased by treatment with Polyopes lancifolia extract in a dose-dependent manner. Also, Polyopes lancifolia extract treatment reduced the overexpressions of inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor-kappa B proteins activation that was induced by high glucose in HUVECs. These results indicate that Polyopes lancifolia extract is a potential therapeutic material that will reduce the damage caused by high glucose-induced-oxidative stress associated with diabetes.

• YAKHAK HOEJI
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• v.42 no.6
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• pp.583-588
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• 1998

These experiments were investigated effects of the cell death of glycyrrhetinic acid (GA) on transplanted-L1210 cells in BALB/c mice. The GA suppressed the proliferation of L121 0 cells in vivo and in vitro system. The administration of GA induced apoptosis of transplanted-L1210 cells via the reduction of mitochondrial transmembrane potential in mice. The GA enhanced the production of nitric oxidation in peritoneal macrophages obtained from L1210 cells-transplanted mice. The apoptosis of L1210 cells were induced by co-culture of the macrophages obtained from GA administered mice and L1210 cells in vitro, and was partly inhibited by the treatment of L-NMMA. These results suggest that GA induces the cytotoxicity and the apoptosis of transplanted-L1210 cells via the production of nitric oxide in peritoneal macrophages.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.3
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• pp.351-358
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• 2014

Pumpkin seed oil (PSO) was investigated for its parasite elimination activity and efficacy in treating disorders of the prostate gland and urinary bladder. We confirmed the composition of PSO and identified its ability to improve vessels. Gas chromatography coupled with mass spectrometric (GC-MS) system was used for PSO composition analysis. Cytotoxicity and cell proliferation were confirmed by Cell Counting Kit-8 (CCK-8) assay. Nitric oxide(NO) production was measured with Griess reagent, and intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 mRNA expression levels were measured by reverse transcription polymerase chain reaction (RT-PCR). As a result, PSO revealed the presence of several components such as linoleic acid, oleic acid, palmitic acid and stearic acid. Cytotoxic effects of PSO were not observed, and PSO increased nitric oxide production in human umbilical vein endothelial cells (HUVEC). Additionally, TNF-${\alpha}$-induced cell proliferation and ICAM-1 expression in HUVEC were inhibited by PSO treatment, whereas VCAM-1 expression was not significantly reduced. Taken together, these results show that PSO is worthy of study as a candidate food material for improvement of vascular disease.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.17-17
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• 2009

Single-walled carbon nanotubes (SWCNTs) have attracted much attention as promising materials for transparent conducting films (TCFs), thanks to their superior electrical conductivity, high mechanical strength, and complete flexibility. The CNT-based TCFs can be used in a variety of application fields as flexible, transparent electrodes, including touch panel screens, flexible electronics, transparent heaters, etc. First of all, this study investigated the effect of a variety of surfactants on the dispersion of SWCNTs in an aqueous solution. Following the optimization of the dispersion by surfactants, flexible TCFs were fabricated by spraying the CNT suspension onto poly(ethylene terephthalate) (PET) substrates. The sheet resistances of the TCFs having different surfactants were investigated with treatment in nitric acid ($HNO_3$) whose concentration and period of treatment time were varied. It seems that the $HNO_3$ removes the surfactants from and is simultaneously doped into the SWCNT network, reducing the contact resistance between CNTs. TCFs were characterized by UV-VIS spectroscopy, thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), and four-point probe.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.254-254
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• 2009

Single-walled carbon nanotubes (SWCNTs) have attracted much attention as promising materials for transparent conducting films (TCFs), thanks to their superior electrical conductivity, high mechanical strength, and complete flexibility. The CNT-based TCFs can be used in a variety of application fields as flexible, transparent electrodes, including touch panel screens, flexible electronics, transparent heaters, etc. First of all, this study investigated the effect of a variety of surfactants on the dispersion of SWCNTs in an aqueous solution. Following the optimization of the dispersion by surfactants, flexible TCFs were fabricated by spraying the CNT suspension onto poly(ethylene terephthalate) (PET) substrates. The sheet resistances of the TCFs having different surfactants were investigated with treatment in nitric acid ($HNO_3$) whose concentration and period of treatment time were varied. It seems that the $HNO_3$ removes the surfactants from and is simultaneously doped into the SWCNT network, reducing the contact resistance between CNTs. TCFs were characterized by UV-VIS spectroscopy, thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), and four-point probe.

• Journal of the Korean institute of surface engineering
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• v.51 no.3
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• pp.172-178
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• 2018

In this paper, effects of potassium permanganate, pottasium dichromate, sodium molybdate on lean duplex stainless steel were studied by GDOES, OCP, potentiodynamic curves. The stainless steels were chemically passivated in each nitric acid solutions containing 4wt.% oxidants for 1 hour. As a result, when potassium dichromate or sodium molybdate was added, content of Fe was decreased and content of Cr was increased. Consequently, corrosion resistance of passive film was increased. But in case of potassium permanganate was added, contrastively, content of Fe was increased and content of Cr was decreased. So corrosion resistance was decreased. Adding sodium molybdate in nitric acid for chemical surface treatment process was the most effective among oxidants and also it showed the most stable anti-corrosion in SST.